Optimizing sampling effort within a systematic design for estimating abundant escapement of sockeye salmon (Oncorhynchus nerka) in their natal river

Publication year: 2008Source: Fisheries Research, Volume 90, Issues 1-3, April 2008, Pages 118-127</br>
Juha, Lilja , Teri, Ridley , George M.W., Cronkite , Hermann J., Enzenhofer , John A., Holmes</br>
The upstream migration of adult sockeye salmon (Oncorhynchus nerka) in the Horsefly River was monitored by a DIDSON imaging sonar during the dominant stock-cycle year 2005 using a systematic 20-minh-1 sampling scheme. We used a subset of these data collected between 16 and 29 September to investigate whether this sampling protocol was justified based on temporal variation in the salmon migration data. During post-processing, the 20-min sequence was split into two 10-min periods and the number of migrating salmon was counted separately. Cross- and autocorrelation analysis showed that estimates from the first and second 10-min samples were similar (r=0.65) and...</br>